A new species of Trichorhina Budde-Lund , 1908 ( Isopoda : Oniscidea : Platyarthridae ) from Paraná caves , southern Brazil

Th e genus Trichorhina Budde-Lund, 1908 in Brazil includes 22 described species, four of which occur in caves. Th e present work aims at describing the fi rst cave species for the state of Paraná. Trichorhina kaingangi n. sp. was collected in Água Boa cave, municipally of Almirante Tamandaré, and Ermida Paiol do Alto cave, municipally of Adrianópolis, both in the Açungui karst area.


introdUction
Until 2004, approximately 300 species of troglobiotic terrestrial isopods (Oniscidea) were known worldwide, mostly described from caves in the northern hemisphere (Taiti, 2004).Biospeleological surveys conducted in the last decades in Australia, Asia and South America have partly modifi ed this scenario and to date 331 troglobiotic Oniscidea species are known (Taiti and Gruber, 2008;Taiti and Xue, 2012;Tabacaru and Giurginca, 2013;Campos-Filho et al., 2014;Taiti 2014;Souza et al., 2015;Taiti and Wynne, 2015).Th is number is certainly not exhaustive, since a large amount of material has been recently collected and many new taxa are still waiting formal descriptions.Th e taxonomic impediment has been the major problem for subterranean research development and cave conservation (Bichuette and Trajano, 2010;Cordeiro et al., 2014).
In the present work the fi rst cave-dwelling species of Trichorhina from the state of Paraná is described.Th e material was collected in Água Boa cave, municipally of Almirante Tamandaré, and Ermida Paiol do Alto cave, municipally of Adrianópolis, both located in the Açungui karst area.

Material and Methods
Specimens are stored in 75% ethanol and identifications are based on morphological characters.Some specimens were dissected and the appendages and pereonites were mounted in micropreparations.Drawings were prepared using a camera lucida.The coordinates of the noduli laterales were obtained and figured as in Vandel (1962).The type material is deposited at Museu de História Natural de Capão da Imbuia (MHNCI), Curitiba, state of Paraná, Brazil, Museu de Zoologia, Universidade de São Paulo (MZUSP), São Paulo, state of São Paulo, Brazil, and Natural History Museum, Section Zoology 'La Specola', Florence, Italy (MZUF).

Study Area
The Açungui karst area is composed of three stratigraphic formations: Capiru, Votuverava and Antinha (Fiori and Gaspar, 1993).The geomorphological evolution of Açungui karst area comprises three main events: (1) the creation of the Purunã Surface; (2) the creation of the Alto Iguaçu Surface; and (3) the opening of the Ribeira River Valley (Alto Ribeira basin), dated from Lower Miocene (Ab'Saber and Bigarella, 1961).The Açungui karst area developed in a uniform geological, geomorphological and climatic environment (Nascimento et al., 2010).The two caves investigated are located in the Alto Ribeira basin, ca.70 km apart, near limestone extraction areas (Fig. 1).
The Água Boa cave belongs to the Capiru Formation, composed mainly of dolomitic limestone.The cave is about 110 m long, very moist with water dripping from the ceiling and forming water puddles in the middle portion.It has two entrances, one of which is used by the mining company which explores the area.The main organic substrates are composed of vegetal matter (entrance and twilight zone) and guano (aphotic zone) of the hematophagous bat Desmodus rotundus (E.Geoffroy, 1810).The bat population in the cave has recently suffered a significant reduction due to chemical control to prevent rabies (Arnone, 2008).Most of the bat guano is old and dry, indicating resource depletion.
The Ermida Paiol do Alto cave is located in the Votuverava formation, composed of calcite limestone.The cave is about 140 m long, with a downhill orientation, contributing to accumulate organic material with different levels of decomposition from the entrance to the twilight zone.The cave has two main conduits and no evidence of hydric activity.Bat guano, probably of the hematophagous bat Diphylla ecaudata Spix, 1823, is present in the twilight and aphotic zones.Fungi are found throughout the cave on the walls and over the bat droppings.Description.Maximum body length 5 mm.Body stout with pereon epimera gradually directed backwards (Fig. 2A).Colourless body.Dorsum surface covered with fan-shaped scale-setae with anastomosed surface (Fig. 2B).One line of noduli laterales inserted close to posterior margins and more or less at same distance from lateral margins of pereonites (Fig. 2B); b/c and d/c coordinates as in Fig. 2C, D. Cephalothorax with well-developed rounded lateral lobes, suprantennal line straight, no frontal line; eyes absent (Fig. 2E, F).Pleon with outline continuous with that of pereon; epimera of pleonites 3-5 well-developed (Fig. 2A).Pleotelson triangular, lateral margins slightly concave and acute apex (Fig. 2G).Antennula of three articles, distal article with nine aesthetascs (Fig. 2H).Antenna when extended posteriorly, reaching posterior margin of pereonite 1; setose longitudinal groove for the water-conducting system (sensu Schmalfuss, 1998) from base of peduncle to distal article of flagellum; flagellum as long as fifth article of peduncle, second article about three times as long as first with two aesthetascs on distal portion, apical organ short with long free sensillae (Fig. 2I).Mandible with molar penicil of about six branches, left mandible with 2+1 penicils, right mandible with 1+1 penicils (Fig. 2J, K).Maxillula inner branch with two penicils; outer branch with 4+5 teeth, all simple (Fig. 2L).Maxilla with setose and bilobate apex; outer lobe about three times as wide as inner lobe, subquadrate and distal margin slightly rounded (Fig. 2M).Maxilliped basis rectangular bearing sparse scale-setae; endite subrectangular, medial seta surpassing distal margin (Fig. 2N).Uropod outer margin grooved bearing glandular pores, exopod slightly longer than endopod (Fig. 3A).Pereopod sternal setae with cleft apex; pereopod 1 with antennal grooming brush transverse reaching median margin of carpus; dactylus with long inner claw, ungual seta with simple apex reaching median portion of outer claw, dactylar seta with simple apex reaching tip of outer claw (Fig. 3B).
As mentioned by Campos-Filho et al. (2014), the assumption of troglobiotic condition in species of Trichorhina is complicated, because most representatives have an endogean way of life, with similar morphological adaptations to troglobiotic forms, i.e. eye reduction/absence and body depigmentation.It is well known that convergent or parallel phenotypic evolution exists between animals living in deep soil and in caves, which can obscure taxonomic relationships (Wilkens and Strecker, 2003;Juan et al., 2010;Campos-Filho et al., 2014).The new species has been found in caves, but more extensive collections in contiguous endogean habitats, which are not usually performed properly in biospeleological surveys, may prove their occurrence outside caves, suggesting a troglophilic rather than a troglobiotic condition.
The Brazilian laws (BRASIL, 1990;2008) guarantee cave preservation when a cave reaches the maximum relevance, and this is only possible when there are rare or endemic troglobiotic species (e.g.Cardoso et al., 2014;Campos-Filho et al., 2014).Thus, although laws protect at least part of the obligate cave fauna, conservation acts cannot come into effect if species remain undescribed.For this reason, taxonomic studies of subterranean species in Brazil are of crucial importance for the preservation of both the environment and the species, and any delay in taxonomic research in caves may yield permanent loss of biodiversity, even before the species are discovered and described (e.g.Bichuette and Trajano, 2005;Fišer et al., 2013;Campos-Filho et al., 2014).
Ecological considerations.In Ermida Paiol do Alto the species occurs throughout the cave, from photic to aphotic zones.The specimens were found on the cave floor and over bat guano, in rainy and dry seasons (Fig. 4).In Água Boa cave the specimens were collected at the entrance and twilight zones, on the cave floor and over decomposing vegetable matter, both in rainy and dry seasons.Trichorhina kaingangi n. sp. was collected together with the introduced species Miktoniscus medcofi (Van Name, 1940) (1♀, MHNCI 4881), which is widely distributed from southern and central USA, Mexico, and Brazilian states of Amapá, Pará, Rio de Janeiro, São Paulo and Rio Grande do Sul (Lemos de Castro, 1971;Araujo and Bueno, 1998;Campos-Filho et al., 2014).